/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.flink.test.recordJobs.graph.pageRankUtil;

import org.apache.flink.api.java.record.io.TextInputFormat;
import org.apache.flink.types.LongValue;
import org.apache.flink.types.Record;

public class ImprovedAdjacencyListInputFormat extends TextInputFormat {
	private static final long serialVersionUID = 1L;

	private final LongValue vertexID = new LongValue();

	private final AsciiLongArrayView arrayView = new AsciiLongArrayView();

	private final LongArrayView adjacentVertices = new LongArrayView();

	@Override
	public Record readRecord(Record target, byte[] bytes, int offset, int numBytes) {

		if (numBytes == 0) {
			return null;
		}

		arrayView.set(bytes, offset, numBytes);

		int numElements = arrayView.numElements();
		adjacentVertices.allocate(numElements - 1);

		try {

			int pos = 0;
			while (arrayView.next()) {

				if (pos == 0) {
					vertexID.setValue(arrayView.element());
				} else {
					adjacentVertices.setQuick(pos - 1, arrayView.element());
				}

				pos++;
			}

			// sanity check
			if (pos != numElements) {
				throw new IllegalStateException("Should have gotten " + numElements + " elements, but saw " + pos);
			}

		} catch (RuntimeException e) {
			throw new RuntimeException("Error parsing: " + arrayView.toString(), e);
		}

		target.clear();
		target.addField(vertexID);
		target.addField(adjacentVertices);

		return target;
	}
}
